VI/143 Galaxy stellar mass assembly (Cousin+, 2015)
Galaxy stellar mass assembly: the difficulty to match observations and
semi-analytical predictions.
Cousin M., Lagache G., Bethermin M., Blaizot J., Guiderdoni B.
<Astron. Astrophys. 575, A32 (2015)>
=2015A&A...575A..32C 2015A&A...575A..32C
Towards a new modelling of gas flows in a semi-analytical model of galaxy
formation and evolution.
Cousin M., Lagache G., Bethermin M., Guiderdoni B.
<Astron. Astrophys. 575, A33 (2015)>
=2015A&A...575A..33C 2015A&A...575A..33C
ADC_Keywords: Models ; Galaxy catalogs
Keywords: galaxies: formation - galaxies: evolution - galaxies: star formation -
galaxies: halos - dark matter - large-scale structure of Universe
Abstract:
Semi-analytical models (SAMs) are currently the best way to understand
the formation of galaxies within the cosmic dark-matter structures.
They are able to give a statistical view of the variety of the
evolutionary histories of galaxies in terms of star formation and
stellar mass assembly. While they reproduce the local stellar mass
functions, correlation functions and luminosity functions fairly well,
they fail to match observations at high redshift (z≥3) in most cases,
particularly in the low-mass range. The inconsistency between models
and observations indicates that the history of gas accretion in
galaxies, within their host dark-matter halo, and the transformation
of gas into stars, are not followed well.
We briefly present a new version of the GalICS semi-analytical model.
With this new model, we explore the impact of classical mechanisms,
such as supernova feedback or photoionization, on the evolution of the
stellar mass assembly and the star formation rate. Even with strong
efficiency, these two processes cannot explain the observed stellar
mass function and star formation rate distribution or the stellar mass
versus dark matter halo mass relation. We thus introduce an ad hoc
modification of the standard paradigm, based on the presence of a
no-star-forming gas component, and a concentration of the star-forming
gas in galaxy discs. The main idea behind the existence of the
no-star-forming gas reservoir is that only a fraction of the total gas
mass in a galaxy is available to form stars. The reservoir generates a
delay between the accretion of the gas and the star formation process.
This new model is in much better agreement with the observations of
the stellar mass function in the low-mass range than the previous
models and agrees quite well with a large set of observations,
including the redshift evolution of the specific star formation rate.
However, it predicts a large amount of no-star-forming baryonic gas,
potentially larger than observed, even if its nature has still to be
examined in the context of the missing baryon problem.
Description:
There are five fits files corresponding to the different models:
- m0 : model without any regulation process
- m1 : reference model (Okamoto et al., 2008MNRAS.390..920O 2008MNRAS.390..920O,
photo-ionization prescription)
- m2 : The Okamoto et al. (2008MNRAS.390..920O 2008MNRAS.390..920O) photo-ionization
prescription is replaced by Gnedin (2000ApJ...542..535G 2000ApJ...542..535G)
prescription
- m3 : SN ejecta processes are based on Somerville et al.
(2008MNRAS.391..481S 2008MNRAS.391..481S) model
- m4 : Model with no-star-forming gas ad-hoc modification
For each model:
- galaxy properties are listed in eGalICS_m*.readme
- data are saved in eGalICS_m*.fits
All data "fits" files are compatible with the TOPCAT software
available on: http://www.star.bris.ac.uk/~mbt/topcat/
If you used data associated to eGalICS semi-analytic model, please
cite the following papers:
* Cousin et al.: "Galaxy stellar mass assembly: the difficulty to match
observations and semi-analytical predictions" (2015A&A...575A..32C 2015A&A...575A..32C)
* Cousin et al.: "Toward a new modelling of gas flows in a
semi-analytical model of galaxy formation and evolution"
(2015A&A...575A..33C 2015A&A...575A..33C)
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 166 5 List of models FITS files
eGalICS_m0.fits 2880 1195728 Model without any regulation process
eGalICS_m0.readme 51 123 Explanations of eGalICS_m0.fits
eGalICS_m1.fits 2880 1195728 Reference model with photo-ionization
prescription of Okamoto et al.
(2008MNRAS.390..920O 2008MNRAS.390..920O)
eGalICS_m1.readme 51 123 Explanations of eGalICS_m1.fits
eGalICS_m2.fits 2880 1195728 Reference model with photo-ionization
prescription of Gnedin (2000ApJ...542..535G 2000ApJ...542..535G)
eGalICS_m2.readme 51 123 Explanations of eGalICS_m2.fits
eGalICS_m3.fits 2880 1195728 SN ejecta processes are based on Somerville
et al. (2008MNRAS.391..481S 2008MNRAS.391..481S) model
eGalICS_m3.readme 51 123 Explanations of eGalICS_m3.fits
eGalICS_m4.fits 2880 1195728 Model with no-star-forming gas ad-hoc
modification
eGalICS_m4.readme 51 123 Explanations of eGalICS_m4.fits
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- FileName Name of the FITS file (11 tables) (1)
17- 19 F3.1 Gibyte Size [3.2] Size of the file
20 A1 --- --- [G]
22- 38 A17 --- Content Name of the file describing the data
40-166 A127 --- Title Title of the model
--------------------------------------------------------------------------------
Note (1): each FITS files contains 11 binary table extensions,
corresponding to 11 values of the redshift, with extnames:
z = 6.143 (table#1 named "ts_08"), 204152 rows
z = 4.000 (table#2 named "ts_14"), 611601 rows
z = 3.000 (table#3 named "ts_19"), 805287 rows
z = 2.030 (table#4 named "ts_27"), 930806 rows
z = 1.778 (table#5 named "ts_30"), 949433 rows
z = 1.128 (table#6 named "ts_41"), 972725 rows
z = 1.000 (table#7 named "ts_44"), 973770 rows
z = 0.299 (table#8 named "ts_71"), 971488 rows
z = 0.099 (table#9 named "ts_82"), 976077 rows
z = 0.020 (table#10 named "ts_92"), 979917 rows
z = 0.000 (table#11 named "ts_94"). 981876 rows
--------------------------------------------------------------------------------
Acknowledgements:
Morgane Cousin, morgane.cousin(at)lam.fr
(End) Patricia Vannier [CDS] 17-Nov-2014